boost中的IPC进程间通信非常好用,可以直接在共享内存上创建对象,相当于new分配器,实测发现它的分配算法还是有点耗时。第一个测试代码仅仅分配一次,然后频繁的复制,每秒钟可以复制4200次左右。
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 | // HelloBoostIPC.cpp : Defines the entry point for the console application. // #include "stdafx.h" #include <boost/interprocess/managed_shared_memory.hpp> #include <boost/interprocess/sync/scoped_lock.hpp> #include <cstdlib> //std::system #include <cstddef> #include <cassert> #include <utility> #include <string> #include <Windows.h> using namespace std; using namespace boost; using namespace boost::interprocess; char dummy[1280*720*3]; class VideoFrame { public: int width; int height; boost::interprocess::interprocess_mutex mutex; char data[1280*720*3]; }; int _tmain(int argc, _TCHAR* argv[]) { int begin, end, n=0; struct shm_remove { shm_remove() { shared_memory_object::remove("MySharedMemory"); } ~shm_remove(){ shared_memory_object::remove("MySharedMemory"); } } remover; managed_shared_memory segment(create_only, "MySharedMemory", sizeof(VideoFrame)*24); VideoFrame *frame = segment.construct<VideoFrame>("frame")(); while(true) { if(n==0) { begin = ::GetTickCount(); } frame->width = 1280; frame->height = 720; scoped_lock<interprocess_mutex> lock(frame->mutex); memcpy(frame->data, dummy, sizeof(dummy)); n++; if(n==1000) { end = ::GetTickCount(); float t = (end-begin)/1000.0f; int rate = (int)(1000/t); printf("write rate=%d\r\n", rate); n = 0; } } segment.destroy<VideoFrame>("frame"); return 0; } |
如果更换成在循环内部分配内存,再释放,则复制频率下降到3200左右。因此在设计大数据量复制的应用程序时,最好不要频繁创建对象和析构对象,这点和进程内的程序开发是一致的。